Evaluation

• Research support

  One strength of the genetic explanation for OCD is the strong evidence base:

  • There is evidence from a variety of sources which strongly suggests that some people are vulnerable to OCD as a result of their genetic make-up - e.g. through twin studies
  • Nestadt et al. reviewed twin studies and found that 68% of identical twins shared OCD as opposed to 31% of non-identical twins
  • Research has found that a person with a family member with OCD is 4x more likely to develop it
  • Therefore, there must be some genetic influence on the development of OCD
• Environmental risk factors

  One limitation of the genetic model of OCD is that there are also environmental risk factors:

  • OCD does not seem to be entirely genetic in origin and it seems that environmental risk factors can trigger or increase the risk of OCD
  • Cromer et al. found that over half of their OCD clients had experienced a traumatic event in their past and that OCD was also more severe in these people
  • Therefore, genetic vulnerability only provides a partial explanation for OCD